Sensing-Based Opportunistic Spectrum Sharing for Cognitive Radio Downlink MIMO Systems

Liang LI  Ling QIU  Guo WEI  

Publication
IEICE TRANSACTIONS on Communications   Vol.E95-B   No.10   pp.3358-3361
Publication Date: 2012/10/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E95.B.3358
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Terrestrial Wireless Communication/Broadcasting Technologies
Keyword: 
cognitive radio,  spectrum sharing,  multiple-input multiple-output (MIMO),  signal-to-leakage-and-noise ratio,  

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Summary: 
In this letter we propose a practical sensing-based opportunistic spectrum sharing scheme for cognitive radio (CR) downlink MIMO systems. Multi-antennas are exploited at the secondary transmitter to opportunistically access the primary spectrum and effectively achieve a balance between secondary throughput maximization and mitigation of interference probably caused to primary radio link. We first introduce a brief secondary frame structure, in which a sensing phase is exploited to estimate the effective interference channel. According to the sensing result and taking the interference caused by the primary link into account, we propose an enhanced signal-to-leakage-and-noise ratio (SLNR)-based precoding scheme for the secondary transmitter. Compared to conventional schemes where perfect knowledge of the channels over which the CR transmitter interferes with the primary receiver (PR) is assumed, our proposed scheme shows its superiority and simulation results validate this.